Lower Diffusion-Induced Stress in Nano-Crystallites of P2-Na2/3Ni1/3Mn1/2Ti1/6O2 Novel Cathode for High Energy Na-ion Batteries

P2-type Na_2/3Ni_1/3Mn_1/2Ti_1/6O₂ (NMTNO) cathode is a preeminent electrode material for Na-ion batteries owing to its open prismatic framework, air-moisture stability, inexpensiveness, appealing capacity, environmental benignity, and Co-free composition. However, the poor cycling stability, sluggish Na-ion kinetics induced in bulk-sized cathode particles, cracking, and exfoliation in the crystallites remain a setback. To outmaneuver these, a designing strategy of a mechanically robust, hexagonal nano-crystallites of P2-type Na_2/3Ni_1/3Mn_1/2Ti_1/6O₂ (NMTNO_nano) electrode via quick, energy-efficient, and low-cost microwave-irradiated synthesis is proposed. For the first time, employing a unified experimental and theoretical approach with fracture mechanics analysis, the mechanism behind the enhanced performance, better structural stability, and lower diffusion-induced stress of NMTNO_nano compared to micro-sized Na_2/3Ni_1/3Mn_1/2Ti_1/6O₂ is unveiled and the electrochemical shock map is predicted. The NMTNO_nano cathode provides 94.8% capacity retention after 100 cycles at 0.1 C with prolonged performance for 1000 cycles at 0.5 C. The practical viability of this cathode, tested in a full cell against a hard carbon anode delivered 85.48% capacity retention at 0.14 mA cm⁻² after 200 cycles. This work bridges the gap in correlating the microstructural and electrochemical properties through experimental, theoretical (DFT), and fracture mechanics analysis, thereby tailoring efficient cathode with lower diffusion-induced stress for high-energy Na-ion batteries.     

Ferulic acid encapsulated chitosan‐tripolyphosphate nanoparticles attenuate quorum sensing regulated virulence and biofilm formation in Pseudomonas aeruginosa PAO1

Pseudomonas aeruginosa is an opportunistic nosocomial pathogenic microorganism causing majority of acute hospital‐acquired infections and poses a serious public health concern. The persistence of bacterial infection can be attributed to the highly synchronised cell‐to‐cell communication phenomenon, quorum sensing (QS) which regulates the expression of a number of virulence factors and biofilm formation which eventually imparts resistance to the conventional antimicrobial therapy. In this study, the anti‐quorum sensing and anti‐biofilm potential of ferulic acid encapsulated chitosan‐tripolyphosphate nanoparticles (FANPs) was investigated against P. aeruginosa PAO1 and compared with native ferulic acid. Dynamic light scattering and transmission electron microscopic analysis confirmed the synthesis of FANPs with mean diameter of 215.55 nm. FANPs showed significant anti‐quorum sensing activity by downregulating QS‐regulated virulence factors. In addition, FANPs also significantly attenuate the swimming and swarming motility of P. aeruginosa PAO1. The anti‐biofilm efficacy of FANPs as compared to native ferulic acid was established by light and confocal laser scanning microscopic analysis. The promising results of FANPs in attenuating QS highlighted the slow and sustained release of ferulic acid at the target sites with greater efficacy suggesting its application towards the development of anti‐infective agents.Inspec keywords: microorganisms, nanofabrication, nanoparticles, nanomedicine, light scattering, cellular biophysics, drugs, antibacterial activity, drug delivery systems, filled polymers, materials preparationOther keywords: size 215.55 nm, ferulic acid encapsulated chitosan‐tripolyphosphate nanoparticles, dynamic light scattering, QS‐regulated virulence factors, cell‐to‐cell communication phenomenon, nosocomial pathogenic microorganism, anti‐quorum sensing activity, Pseudomonas aeruginosa PAO1, anti‐infective agents, confocal laser scanning microscopic analysis, anti‐biofilm efficacy, transmission electron microscopic analysis, native ferulic acid, FANPs, anti‐biofilm potential, conventional antimicrobial therapy, bacterial infection, acute hospital‐acquired infections, biofilm formation     

Volatiles of <Emphasis Type="Italic">Solena amplexicaulis</Emphasis> (Lam.) Gandhi Leaves Influencing Attraction of Two Generalist Insect Herbivores

Epilachna vigintioctopunctata Fabr. (Coleoptera: Coccinellidae) and Aulacophora foveicollis Lucas (Coleoptera: Chrysomelidae) are important pests of Solena amplexicaulis (Lam.) Gandhi (Cucurbitaceae), commonly known as creeping cucumber. The profiles of volatile organic compounds from undamaged plants, plants after 48 hr continuous feeding of adult females of either E. vigintioctopunctata or A. foveicollis, by adults of both species, and after mechanical damaging were identified and quantified by GC-MS and GC-FID analyses. Thirty two compounds were detected in volatiles of all treatments. In all plants, methyl jasmonate was the major compound. In Y-shaped glass tube olfactometer bioassays under laboratory conditions, both insect species showed a significant preference for complete volatile blends from insect damaged plants, compared to those of undamaged plants. Neither E. vigintioctopunctata nor A. foveicollis showed any preference for volatiles released by heterospecifically damaged plants vs. conspecifically damaged plants or plants attacked by both species. Epilachna vigintioctopunctata and A. foveicollis showed attraction to three different synthetic compounds, linalool oxide, nonanal, and E-2-nonenal in proportions present in volatiles of insect damaged plants. Both species were attracted by a synthetic blend of 1.64 μg linalool oxide?+?3.86 μg nonanal?+?2.23 μg E-2-nonenal, dissolved in 20 μl methylene chloride. This combination might be used as trapping tools in pest management strategies.     

Nature of thermodynamic fluctuations in the electrical conductivity of Y-Ba-Cu-O pellets and tapes containing silver

Results on the temperature dependence of the electrical resistivity of single-phase silver-doped Y-Ba-Cu-O pellets and tapes, prepared by a coprecipitation technique, are presented. The excess electrical conductivity nearT>T _c is analyzed using Aslamzov-Larkin (AL) formulations. Silver addition in Y-Ba-Cu-O influences strongly the temperature range of both the 3D and 2D regions. The lower limit of the breakdown temperature of the mean-field region (x=–0.5) shifts toward higher temperatures as the concentration of Ag increases in Y-Ba-Cu-O. For samples with higher Ag contents, a third region with critical exponent x=–0.28 is seen beyond the mean-field region. This possibly indicates the appearance of a fully critical 3D region, where dynamic scaling theory applies.     

Electrical properties of Na1/2Nd1/2TiO3 Ceramics

The polycrystalline sample of Na_1/2Nd_1/2TiO₃ was prepared by a high-temperature solid-state reaction technique. The formation of the compound was confirmed by both XRD and EDX studies. Preliminary structural analysis ofNa_1/2Nd_1/2TiO₃ using X-ray diffraction data exhibits a tetragonal phase of the material at room temperature. The dielectric permittivity and the loss tangent of the pellet sample were obtained in a wide frequency range (1 kHz to 1 MHz) at different temperatures (30 °C to 425 °C). The dielectric anomaly at 114 °C, appearance of hysteresis loop and piezoelectric properties at room temperature confirmed the ferroelectric properties of the compound. Measurements of frequency and temperature dependence of impedance over a wide frequency range (100Hz–1MHz) were carried out by complex impedance spectroscopy as a non-destructive tool and indicate that the electrical properties of the material are strongly temperature dependent. Evidence of temperature dependence of electrical relaxation phenomenon as well as the negative temperature coefficient (NTC)-type of resistance behavior of the sample has also been observed. The dc conductivity graph follows the Arrhenius law. Studies of dielectric modulus suggest the non-Debye type of relaxation in the materials, which is supported by the impedance data.     

Oleogels Based on Palmitic Acid and Safflower Oil: Novel Formulations for Ocular Drug Delivery of Voriconazole

The gelation of the vegetable oils using fat crystals has gained significant attention in recent years. These formulations have been explored for food and pharmaceutical applications. The alteration in the properties of palmitic acid (20–40% w/w) and safflower oil oleogels is extensively studied at microscopic and macroscopic levels. The thermal and mechanical stability of the oleogels is improved when the proportion of the palmitic acid content is increased. However, under stress, the fat crystal network junction zones of the oleogels with higher proportions of palmitic acid undergo disruption. The changes in the properties of the oleogels are due to the alteration in the molecular packing, crystallite size, and lattice strain of the fat crystal network. The alteration in the properties is governed by the changes in the extent of inter‐ and intramolecular hydrogen bonding within the components of the oleogels. The oleogels can demonstrate the ability to deliver the drug, voriconazole, across the corneal tissue. Further, the prepared oleogels are biocompatible to murine fibroblast cells and do not elicit adverse reactions when instilled within the ocular sac of rabbits. The results suggest that the oleogels can be tried as ocular delivery vehicles. Practical Applications: The delivery of drug into the internal structure of the eye is a great challenge for the ophthalmologists. Usually no more than 1% of the drug can be delivered through conventional techniques. Various researchers have proposed the use of lipid‐based ocular drug delivery systems. Some of them include solid liquid nanoparticles, emulsions, and liposomes. However, the preparation of these formulations requires a tedious process. Keeping this in mind, it is proposed to synthesize oleogel as probable ocular drug delivery system.     

The Uniqueness of Tryptophan in Biology: Properties,Metabolism, Interactions and Localization in Proteins

Tryptophan (Trp) holds a unique place in biology for a multitude of reasons. It is the largest of all twenty amino acids in the translational toolbox. Its side chain is indole, which is aromatic with a binuclear ring structure, whereas those of Phe, Tyr, and His are single-ring aromatics. In part due to these elaborate structural features, the biosynthetic pathway of Trp is the most complex and the most energy-consuming among all amino acids. Essential in the animal diet, Trp is also the least abundant amino acid in the cell, and one of the rarest in the proteome. In most eukaryotes, Trp is the only amino acid besides Met, which is coded for by a single codon, namely UGG. Due to the large and hydrophobic π-electron surface area, its aromatic side chain interacts with multiple other side chains in the protein, befitting its strategic locations in the protein structure. Finally, several Trp derivatives, namely tryptophylquinone, oxitriptan, serotonin, melatonin, and tryptophol, have specialized functions. Overall, Trp is a scarce and precious amino acid in the cell, such that nature uses it parsimoniously, for multiple but selective functions. Here, the various aspects of the uniqueness of Trp are presented in molecular terms.     

Electro-mechanical interactions during erosion–corrosion

This study aims to understand the physical processes invoked when solid particle erosion occurs in a corrosive media. The literature on wear-corrosion shows some effort has been placed in qualifying the interactions between erosion and corrosion leading to ‘synergistic’, ‘additive’ and ‘antagonistic’ terms. These terms are difficult to quantify experimentally with multiple experiments being required and generate considerable errors often suggesting these interactive terms are negligible. Hence the current work seeks to investigate these interactions, the errors associated with their measurement and gain understanding of the processes involved by careful examination of microstructural and mechanical property changes of surfaces subjected to erosion–corrosion. Cast nickel–aluminium bronze/NaCl solution has been chosen to study as this system has been studied at Southampton for several years. In situ electrochemical, gravimetric and topographical analyses have been evaluated and discussed using microstructural and hardness measurements.     

Inhibition of Viral RNA-Dependent RNA Polymerases by Nucleoside Inhibitors: An Illustration of the Unity and Diversity of Mechanisms

RNA-dependent RNA polymerase (RdRP) is essential for the replication and expression of RNA viral genomes. This class of viruses comprise a large number of highly pathogenic agents that infect essentially all species of plants and animals including humans. Infections often lead to epidemics and pandemics that have remained largely out of control due to the lack of specific and reliable preventive and therapeutic regimens. This unmet medical need has led to the exploration of new antiviral targets, of which RdRP is a major one, due to the fact of its obligatory need in virus growth. Recent studies have demonstrated the ability of several synthetic nucleoside analogs to serve as mimics of the corresponding natural nucleosides. These mimics cause stalling/termination of RdRP, or misincorporation, preventing virus replication or promoting large-scale lethal mutations. Several such analogs have received clinical approval and are being routinely used in therapy. In parallel, the molecular structural basis of their inhibitory interactions with RdRP is being elucidated, revealing both traditional and novel mechanisms including a delayed chain termination effect. This review offers a molecular commentary on these mechanisms along with their clinical implications based on analyses of recent results, which should facilitate the rational design of structure-based antiviral drugs.     

A compact substrate integrated waveguide backed self‐quadruplexing antenna for C‐band communication

This article presents a simple, compact, and lightweight substrate integrated waveguide (SIW) backed self‐quadruplexing antenna for quad‐band applications. The design procedure is straightforward. Topside of the SIW cavity is modified to form four patches of different lengths which are fed separately by four 50‐Ω microstrip feed lines and operate at 5.14, 5.78, 6.74, and 7.74. It attains 4.1, 4.96, 6.2, and 6.1 peak gain at the above frequencies, respectively. The observed front‐to‐back‐ratio is more than 17.5 dB and the isolation level is above 28 dB. This antenna topology allows to redesign each resonant frequencies as per application requirement using a single parameter and without disturbing other performances. Design guidelines for developing the proposed antenna are provided. A prototype antenna is fabricated using RT‐Duroid (5870) substrate and characterized for validation. The proposed antenna is suitable for handheld microwave devices for C‐band communication.